阅读说明：本技术 一种大腔体压机制备宝石级矿物烧结体的方法 (Method for preparing gem-grade mineral sintered body by large-cavity press ) 是由 刘兆东 侯旭远 刘冰冰 姚明光 尚宇琛 陈陆瑶 沈方韧 于 2020-05-06 设计创作，主要内容包括：本发明的一种大腔体压机制备宝石级矿物烧结体的方法,属于功能材料制备的技术领域。制备方法包括微米级氧化物颗粒的混合、初始玻璃的制备、样品仓的特殊设计、利用大腔体压机的高温高压反应、淬火、抛光等步骤。本发明能够制备毫米尺寸宝石级矿物烧结体,制备的样品烧结完好致密,呈透明或半透明状,样品表明无裂缝,可稳定存在于常温常压环境中；本发明操作简单,无生物毒性,对于研究宝石级矿物的弹性、电导率等物理和化学性质以及工业应用具有重要意义。(The invention discloses a method for preparing a gem-grade mineral sintered body by using a large-cavity press, and belongs to the technical field of functional material preparation. The preparation method comprises the steps of mixing micron-sized oxide particles, preparing initial glass, specially designing a sample bin, utilizing a large-cavity press to perform high-temperature and high-pressure reaction, quenching, polishing and the like. The method can prepare the millimeter-sized gem-grade mineral sintered body, the prepared sample is well and compactly sintered and is transparent or semitransparent, and the sample shows no crack and can stably exist in the normal-temperature and normal-pressure environment; the method is simple to operate, has no biological toxicity, and has important significance for researching physical and chemical properties of the gem grade minerals such as elasticity, conductivity and the like and industrial application.)

1. A method for preparing a gem-grade mineral sintered body by a large-cavity press comprises the following steps:

1) mixing micron-level magnesium oxide with the grain size of less than 3 mu m, silicon dioxide and other metal oxides according to the stoichiometric ratio of a target mineral sintered body to be prepared, preserving the heat at 1700 ℃ for 10-30 minutes, and quenching the mixture into water or liquid nitrogen to obtain an initial glass material;

2) grinding the obtained initial glass material into micron powder, putting the micron powder into a cylindrical die, and pressing the micron powder into a cylinder;

3) using a gold tube or boron nitride as a sample bin, putting the cylinder prepared in the step 2) into the sample bin, pressurizing to 15-25 GPa by using a large-cavity press, heating to 900-1700 ℃, and preserving heat and pressure for 1-2 hours;

4) quenching to room temperature, or rapidly cooling to 400-500 ℃, and releasing pressure for 12-15 hours to room pressure at room temperature or at the temperature of 400-500 ℃.

5) And taking out the sample, and polishing the surface of the sample to a crystal face by using a micron-sized diamond polishing solution to obtain the gem grade mineral sintered body.

2. The method for preparing the gem grade mineral sintered body by the large-cavity press as claimed in claim 1, characterized in that in step 1), the other metal oxide is Fe₂O₃And/or Al₂O₃。

3. The method for preparing the gem grade mineral sintered body by the large-cavity press as claimed in claim 1 or 2, characterized in that in step 5), the diamond polishing solution is 1-3 μm.

Technical Field

The invention belongs to the technical field of functional material preparation, and particularly relates to a method for preparing a gem-grade mineral sintered body by using a large-cavity press.

Background

With the development of science and technology and the improvement of human material level, the demand of human beings on precious stones is gradually increased, and precious stones can be widely applied to industrial science and technology and life, however, the resources of natural precious stones are limited, so that the artificial synthesis of precious stone minerals is an important path. Researches show that the large-cavity press can compact loose materials under high pressure by pressing under the extreme environment of high temperature and high pressure, and re-nucleate, grow and sinter at high temperature, so that the large-cavity press is one of important tools for preparing large-size gem grade minerals. At present, a large-cavity press can prepare nano polycrystalline diamond with the diameter and height of 1cm and polycrystalline cubic boron nitride with the height of 2-3mm, and can be applied to cutting tools and the computer industry.

At present, the prepared gem grade mineral sintered body is mainly sintered under the environment of low temperature and low pressure, although the sintered size is larger, the particle size of the sintered body is larger, so that the compactness is poor, cracks can appear, and the physical properties of the sintered body, including hardness, toughness, elasticity and the like, are seriously influenced. The high temperature and high pressure solid reaction method of the large cavity press can overcome the defects. At present, a plurality of sintered compact bodies (such as nano polycrystalline diamond and cubic boron nitride) are prepared by utilizing a high-pressure technology of a large-cavity press, but the synthesis of a high-quality gem-grade mineral sintered body under high pressure is very difficult, excessive high-pressure phases and stress are generated due to the high pressure, and the high-temperature high-pressure sintered body is very easy to crack due to the existence of the stress, so that the physical property research of a sample is hindered. Therefore, the synthesis of high-quality, large-size and gem-grade sintered mineral bodies and the exploration of new functions related to the structure have important significance on solid chemistry, physics and material science.

Disclosure of Invention

In order to overcome the defects in the background technology, the invention provides a method for preparing a large-size gem-grade compact sintered body by using a large-cavity press.

The technical scheme of the invention is as follows:

a method for preparing a gem-grade mineral sintered body by using a large-cavity press comprises the following steps:

1) mixing micron-level magnesium oxide with the grain size of less than 3 mu m, silicon dioxide and other metal oxides according to the stoichiometric ratio of a target mineral sintered body to be prepared, preserving the heat at 1700 ℃ for 10-30 minutes, and quenching the mixture into water or liquid nitrogen to obtain an initial glass material;

2) grinding the obtained initial glass material into micron powder, putting the micron powder into a cylindrical die, and pressing the micron powder into a cylinder;

3) using a gold tube or boron nitride as a sample bin, putting the cylinder prepared in the step 2) into the sample bin, pressurizing to 15-25 GPa by using a large-cavity press, heating to 900-1700 ℃, and preserving heat and pressure for 1-2 hours;

4) quenching to room temperature, or rapidly cooling to 400-500 ℃, and releasing pressure for 12-15 hours to room pressure at room temperature or at the temperature of 400-500 ℃.

5) And taking out the sample, and polishing the surface of the sample to a crystal face by using a micron-sized diamond polishing solution to obtain the gem grade mineral sintered body.

In step 1), the other metal oxide is preferably Fe₂O₃And/or Al₂O₃。

In the step 5), the diamond polishing solution used is preferably 1-3 μm.

Has the advantages that:

1. the method can be used for preparing the gem grade mineral sintered body, the prepared sample is pure phase, and the size reaches 1-2 mm grade.

2. The mineral sintered body prepared by the invention is completely and compactly sintered and is transparent or semitransparent, and a sample shows no crack.

3. The mineral sintered body prepared by the invention can stably exist in normal temperature and normal pressure environment.

4. The invention has simple operation and no biological toxicity.

5. The invention has important significance for researching the crystal structure and the physical properties related to the structure of the mineral sintered body and exploring new functions related to the structure.

Drawings

Fig. 1 is a schematic view of the assembly design of the high-temperature high-pressure equipment used in the present invention.

FIG. 2 shows the sintered minerals MgSiO in gem grade prepared in examples 1 and 2₃And Mg₃Al₂Si₃O₁₂Optical photographs of garnets.

FIG. 3 is the Gem grade sintered mineral MgSiO prepared in example 3₃Optical photographs of the perovskites.

FIG. 4 shows a gemstone-grade sintered mineral (Mg) prepared in example 4_0.9Fe_0.1)(Al_0.1Si_0.9)O₃Optical photographs of the perovskites.

FIG. 5 is the Gem grade sintered mineral Mg prepared in example 5_0.95Al_0.1Si_0.95O₃Optical photograph of the autumn stone.

FIG. 6 is an XRD spectrum of the sintered garnet prepared in example 1 and example 2.

FIG. 7 is an XRD spectrum of sintered aubergite and perovskite prepared in examples 3 to 5.

FIG. 8 is a secondary electron scan of the garnet, aubergite and perovskite phases prepared in examples 1, 2, 4 and 5.

Detailed Description

The invention is further illustrated with reference to specific embodiments below.